Gridded SST products developed particularly for offshore regions are increasingly being applied close to the coast for biogeographical applications. The purpose of this paper is to demonstrate the dangers of doing so through a comparison of reprocessed MODIS Terra and Pathfinder v5.2 SSTs, both at 4 km resolution, with instrumental in situ temperatures taken within 400 m from the coast. We report large biases of up to +6°C in places between satellite-derived and in situ climatological temperatures for 87 sites spanning the entire ca. 2 700 km of the South African coastline. Although biases are predominantly warm (i.e. the satellite SSTs being higher), smaller or even cold biases also appear in places, especially along the southern and western coasts of the country. We also demonstrate the presence of gradients in temperature biases along shore-normal transects — generally SSTs extracted close to the shore demonstrate a smaller bias with respect to the in situ temperatures. Contributing towards the magnitude of the biases are factors such as SST data source, proximity to the shore, the presence/absence of upwelling cells or coastal embayments. Despite the generally large biases, from a biogeographical perspective, species distribution retains a correlative relationship with underlying spatial patterns in SST, but in order to arrive at a causal understanding of the determinants of biogeographical patterns we suggest that in shallow, inshore marine habitats, temperature is best measured directly.
Ophiuroid research in South Africa has not kept pace with global taxonomic research with the last major taxonomic review of the group being published in 1976. This paper documents all new records of Ophiuroidea from South Africa since (and including) 1977. These records originate from specimens housed in five zoological collections, from photographic records and from reports published in the non-taxonomic literature. A short review of the history of ophiuroid taxonomy in South Africa is also given and for each new record, key references, distribution, ecology, additional notes and, where possible, photographs, are presented. This has resulted in an additional 24 species being recorded within the mainland Exclusive Economic Zone of South Africa, elevating the total known number of ophiuroid species reported in the region to 137.
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